A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
This disclosure includes a Microfiche Appendix containing computer program listings consisting in total of one (1) sheet of microfiche including eighty-two (82) total frames which are expressly incorporated herein by reference in their entirety to form part of the present disclosure.
1. Field of the Invention
The present invention relates generally to radio transmission systems and, in particular, to a method and apparatus for wirelessly transmitting digital information that may be employed in wireless point-of-sale vending systems, such as pay-at-the-pump fuel dispensing systems.
2. Background of the Disclosure
Reflecting an ongoing effort to provide retailers and others with a competitive advantage, various types of cashless vending systems are known in the art. For example, some vending machines are equipped with card reading devices that enable the machines to accept payments using credit cards and/or debit cards. The ability to accept cashless payments provides a number of important advantages. Vendors are able to make sales to persons who may not possess cash or coinage in necessary amounts or denominations and can gain access to valuable data on buying behaviors. Consumers benefit by being required to carry less cash and by being provided with complete records of card transactions by the card issuer. Unlike cash, which can also be lost or stolen, credit card users benefit from various laws intended to protect cardholders from unauthorized purchases and other forms of fraud involving their accounts. Card purchases may also afford the consumer access to discounts, rebates, or other special incentive programs which are commonly linked to card usage.
In order to realize such advantages, it is known to provide fuel dispensers at filling stations with magnetic card reading devices for the purpose of accepting purchases to be charged to a credit or debit card account. One manufacturer of fuel dispensers, Gilbarco, Inc. of Greensboro, N.C., offers a card reading device under the trademark xe2x80x9cCRINDxe2x80x9d that includes a card receptacle to accept the magnetic card and also happens to accept cash. In addition to the advantages just noted, providing card reading devices directly at the xe2x80x9cgas pumpxe2x80x9d allows customers to make their purchases quickly without the need to walk to a cashier (possibly subjecting one to inclement weather), wait in line, or count change.
In an effort to provide an even greater degree of speed and convenience to customers, one major oil company has recently introduced another system to facilitate the vending of fuel at filling stations. This system, which typically augments rather than replaces the magnetic card reading devices already present at the pump, is presently being promoted under the trademark xe2x80x9cSPEEDPASSxe2x80x9d. The xe2x80x9cSPEEDPASSxe2x80x9d system is based on radio frequency identification (RFID) technology marketed by Texas Instruments under the trademark xe2x80x9cTIRIS.xe2x80x9d xe2x80x9cTIRISxe2x80x9d technology has also reportedly been employed to track items in a variety of material handling systems and to automatically assess tolls to vehicles on toll roads without the necessity of stopping the vehicle.
Customers interested in using the xe2x80x9cSPEEDPASSxe2x80x9d fuel vending system enroll by filling out a form that requests information identifying a credit card account to which purchases made using the system are to be posted. This credit card information is electronically encoded into a high frequency (2.45 GHz) radio frequency (RF) transponder device that is small enough to be attached to a key ring or carried in some other manner by the consumer to whom the device is issued. The fuel dispensers at participating filling stations are provided internally with a receiving unit having an antenna mounted beneath a designated area on the external surface of the dispenser. The designated area is prominently marked with identifying indicia and printed instructions for using the xe2x80x9cSPEEDPASSxe2x80x9d system. The instructions direct the consumer to bring the transponder device into proximity of the designated area. When this is done, the receiving unit within the dispenser picks up the encoded account information transmitted by the transponder device. Once the information is appropriately decoded, it is used to authorize a purchase and, at an appropriate time (such as on completion of the dispensing operation), to post relevant information relating to the purchase (such as the amount of the purchase, the time of day the purchase was made and the like) to the corresponding account of the customer. The purchase is subsequently reflected on an invoice or billing statement provided by the credit card company or other entity.
While systems, such as the xe2x80x9cSPEEDPASSxe2x80x9d system, may offer an incremental improvement in speed and convenience over use of a credit card, they also suffer certain drawbacks. Notably, if the transponder is lost or stolen, it can be used without authorization at any participating station. The use of off-the-shelf transponder devices may also present a security risk. Such risk may be reduced by encoding the transponder with a secondary account number that identifies, but does not actually represent, an actual credit card or debit account number. While secondary account encoding affords additional security, such an approach limits or complicates universal acceptance of the system by vendors other than the issuer of the transponder due to the need to make available to other vendors a database cross referencing the actual and secondary account numbers. It is a disadvantage to the consumer to be limited to use of the system with only a single vendor. It is likewise undesirable to require a consumer to carry multiple transponders in order to make purchases from a corresponding multiple number of vendors.
Systems utilizing a high frequency RF carrier are also of limited utility due to problems associated with the electric field shielding effects of vehicle bodies and/or metallic structures used in and around fuel pumps. Such shielding effects require that the transponder units be located other than within electrically shielded areas and limit the effective range and/or reliability of signal transmission and/or reception. Such shielding problems are not satisfactorily addressed by attempts to locate the transponder or other signaling device at some secure, but inconspicuous, location on the exterior of a vehicle. In such a location, the signaling device would be exposed to harsh conditions including temperature and humidity extremes, precipitation, icing and an increased risk of damage from physical impact. Locating the device inside the compartment which houses the fuel cap of the vehicle would subject the device to the electric field shielding problems already noted.
Therefore, a need exists for a method and apparatus for transmitting a digital information signal that permit transmission of digital information (e.g., a credit card account number) from substantially electrically shielded environments, such as fuel cap compartments or automobile trunks, thereby facilitating temporary or permanent attachment of such an apparatus within electrically shielded environments, and that provides the flexibility necessary to permit a transmitter employing such a method to be used in vending systems of multiple vendors. A vending system that employs such a method and apparatus would also be an improvement over the prior art.
In view of the foregoing problems and limitations of the prior art, it is one object of the present invention to provide a transmission system for digital information that permits such digital information to be transmitted from a substantially electrically shielded environment. In one aspect of the present invention, a constant frequency generator generates a constant frequency signal, a phase modulator varies the instantaneous phase of the constant frequency signal based on the digital information, and a resonant circuit including an antenna averages the phase modulated signal to simulate a frequency modulated (FM) signal that includes the digital information. In another aspect of the present invention, the simulated FM signal is transmitted from the antenna primarily via a magnetic field at a carrier frequency of about ten kilohertz or less, thereby enabling the transmission of the digital information from an electrically shielded environment, such as from inside the trunk of an automobile. In a further aspect of the present invention, the phase modulator varies the instantaneous phase of the constant frequency signal by transitioning the constant frequency signal through at least two phases during any one bit transmission period to facilitate detection of the digital information using very low cost small scale integrated (SSI) circuits.
It is another object of the present invention to provide a product vending system in which the aforesaid method and apparatus may be utilized. The product vending system preferably includes a card reading device that, in response to obtaining billing information for a consumer to be charged for the product, provides the billing information to a creditor of the consumer; a receiver for receiving a radio signal from a transmitter associated with a receptacle for the product; a card reader interface, operably coupled to the receiver and the card reading device, that determines whether the radio signal includes billing information for the consumer to be charged and, in response to determining that the radio signal includes the billing information, converts the billing information received from the receiver into a format compatible with the card reading device and generates a control signal to enable the product dispenser to dispense the product; and a transmitter, operably coupled to the card reader interface, that transmits, responsive to at least one control signal from the card reader interface, at least one interrogation signal that includes a request for the billing information.
It is a further object of the present invention to incorporate a jamming circuit into the product vending system, wherein the jamming circuit is coupled to the card reader interface and transmits a jamming signal to prevent the receiver from receiving the radio signal until at least a portion of the product dispenser is in sufficient proximity to the receptacle to permit reception of the radio signal.
It is yet another object of the present invention to provide a product vending system that utilizes half-duplex radio signaling to dispense a product from a dispenser to a receptacle for the product. Such a product vending system includes a transaction controller that generates control signals to facilitate dispensing of the product from the dispenser; a first transmitter, operably coupled to the transaction controller and forming a part of the dispenser, that transmits an interrogation signal responsive to a control signal from the transaction controller, the interrogation signal including a request for billing information of a consumer to be charged for the product; a first receiver, locatable in a substantially electrically shielded environment that is physically associated with the receptacle, that receives the interrogation signal; a second transmitter, operably coupled to the first receiver, that transmits a radio signal responsive to receipt of the interrogation signal, the radio signal including the billing information; and a second receiver, operably coupled to the transaction controller, that receives the radio signal, demodulates the radio signal to recover the billing information, and provides the billing information to the transaction controller.
These and other objects and advantages of the invention will become apparent to the person of ordinary skill in the art upon review of the following detailed description of a preferred embodiment taken in conjunction with the appended drawings in which like reference numerals designate like items.